Simulative method for the optical processor reconfiguration on a dynamically reconfigurable optical platform

With the reconfiguration technique, users can configure the optical processor of a new optical computing platform, the ternary optical computer (TOC), into 42 specific basic operation units, and reconfigure it when the computation is completed. A simulative method of software for this technique is proposed in this paper. Also, an elaborate experiment based on this software is discussed. This simulation of reconfiguration demonstrates that the theory of reconfiguring optical processor in TOC is valid and also lays the foundation for the hardware implementation of the reconfiguration technique.     

Control of optical properties of silica glass synthesized by VAD method for photonic components

High-purity silica glass (SiO₂) synthesized by vapor-phase methods has been extensively used as optical material for photolithography due to its high transmittance in the UV range. Furthermore, low birefringence is an essential property in order to attain distortion-free images of fine IC patterns. This research reports the development of low birefringence silica glass for photonic components that excludes the annealing requirement by controlling the processing parameters of the VAD (Vapor-phase Axial Deposition) method. Nanoparticles size radial homogeneity of silica soot boules was characterized by scanning electron microscopy (SEM). It was established a relationship with the birefringence of consolidated boules characterized through polarization spectrophotometry. As the most interesting results, low birefringence silica glass (? 2 nm/cm) was synthesized with reduced fabrication time and cost besides simple processing stages by controlling the silica boule bottom shape during deposition processing in correlation with the consolidation time.     

Simple high-precision method for measuring the specular reflectance of optical components

We present a simple method to determine precisely the specular reflectance of optical components. The absence of transmissive elements in this method makes a wide spectral range available. High accuracy and precision are achieved with a fast, periodic change between the reference beam and the probe beam. Special efforts were made to eliminate inhomogeneities of beam intensity and detector sensitivity. With our experimental setup we obtain a precision of ±3 × 10(-4) at the wavelength of 10.6 μm and ±3 × 10(-5) at 1.06 μm for a single-bounce-measuring setup.     

An interference method for measuring parallelism of miniature optical components

A method for measuring parallelism of transparent optical components with small aperture size is described. It uses a Haidinger-type laser interferometer adapted for the measurement of optical components with millimeter and sub-millimeter aperture size. The method is based on the measurement of the optical thickness variation when the plate under test is translated across a focused laser beam. Measurement results for optical parts with 0.8 mm–10 mm aperture size are presented.     

Low-loss reconfigurable OADM for metro core optical network

Reconfigurable optical add/drop multiplexers (ROADMs) will play a key role in next-generation dynamically provisioned wavelength networks. Existing ROADM subsystems, manufactured with different designs and technologies, are suffering from either high insertion losses, especially for the passing-through (express)-channels, or high manufacturing costs that are preventing their rapid deployment in networks. An architecture for an ROADM subsystem that integrates the best features of the latest available ROADM designs is proposed. The proposed ROADM subsystem, denoted as a Hybrid-ROADM, exhibits a lower insertion loss (~7 dB for express-channels) than existing ROADMs while offering simplification and cost benefit. A metro network testbed has been configured to demonstrate and compare the performance of the proposed Hybrid-ROADM module against currently available ROADM subsystems. The obtained results indicate that our Hybrid-ROADM shows better performance in metro networks than the latest available ROADM subsystems and will reduce the overall network operating costs.     

一种面向可重构ERP系统的作业成本法

在对传统企业资源计划(ERP)中的成本方法和传统作业成本法的缺点进行分析的基础上,提出了一种面向可重构ERP系统的作业成本法.该方法建立在广义工作中心的动态可扩展结构基础之上,由将企业资源消耗分配到基本工作中心、将基本工作中心资源消耗分配到作业、将作业资源消耗分配到成本对象以及各级广义工作中心成本滚加计算等四个步骤组成.该方法继承了传统作业成本法面向过程的特点,能够支持过程重构驱动的ERP系统企业内和企业间重构,实现了最大程度降低过程结构成本.算例表明,与传统制造成本法和作业成本法相比,该方法能够为可重构ERP系统提供更有效、准确和集成化的成本信息和决策支持.     

A reconfigurable platform in support of one-of-a-kind product development

In recent years, a variety of Internet-based systems has been developed for the purpose of Rapid One-of-a-Kind or customized Product Development (ROKPD). They can be applied in different stages of the product development process such as to rapidly capture customer requirements, and help produce high-quality products at low cost and short lead-time. Many of the systems, however, do not support rapid adaptation or dynamic reconfiguration of systems and tools for supporting ROKPD in a distributed manufacturing environment. To the authors’ knowledge, the infrastructure of such a reconfigurable platform for supporting distributed manufacturing has never been directly studied. This paper proposes an Internet-based reconfigurable ROKP platform that has been prototyped to serve as a substrate for integrating innovative tools and systems for One-of-a-Kind Production (OKP) companies in New Zealand. The main emphasis of this paper is to investigate how to build the Internet-based reconfigurable ROKPD platform and to design appropriate intelligent tools and systems for the purpose of rapidly and economically producing OKP products in the global environment. A number of recent developments are discussed, including the four open-domain infrastructure of the ROKPD platform, Internet-based data management systems, an integrated product data environment and a cost/lead time control tool.     

Correlation platform for optical nondestructive monitoring

Translated from Izmeritel'naya Tekhnika, No. 3, pp. 16–18, March, 1989.     

Dispersion compensation for high bit rate fiber-optic communication using a dynamically tunable optical filter

A detailed analysis of dispersion-compensating fiber-optic filter is provided. Design parameters of the filter that could provide dispersion compensation for wide spectral sources are discussed. The dispersion-compensating fiber filter designed here can be dynamically tuned to compensate for the drift in the laser center frequency caused by temperature change and other deteriorations. The filter can be fabricated by exposing the photorefractive fibers to ultraviolet radiation. A design methodology for fabricating the refractive-index variation along the longitudinal direction of the fiber with appropriate chirp and taper coefficients is also given here. Dispersion-compensation capability of the fiber filter is demonstrated by simulating pulse broadening after transmission in a long fiber and the regeneration of the pulse after dispersion compensation.     

Three-dimensional sensing based on a dynamically focused laser optical feedback imaging technique

A new method analogous to three-dimensional confocally based sensing is proposed. This method uses the technique of laser optical feedback imaging, which takes advantage of the resonant sensitivity of a short-cavity laser to frequency-shifted optical feedback for highly sensitive detection, making it ideal for surface and volume measurements of noncooperative targets. Rapid depth scanning is made possible by use of an electrically controlled variable-focus lens. The system is able to detect height discontinuities, and because detection occurs along the axis of projection the system does not have problems of shadow. Preliminary results for a depth range of 15 mm and a resolution of 100 mum are presented.     

Considerations for tolerancing aspheric optical components

Optical designs often specify both surface form and centering (tilt and lateral displacement) tolerances on aspheric surfaces. In contrast to spherical surfaces, form and centering errors are coupled for aspheric surfaces. Current standards do not specify how to interpret such tolerances, and in particular they do not define the position of an aspheric surface that has form errors. The straightforward definition that uses the best-fit surface position that minimizes rms error has subtle problems. The best-fit surface position for aspheric surfaces is influenced by power error and can be highly sensitive to surface form errors when the derivative of aspheric departure is small. We analyze the conditions under which form and centering tolerances may be considered compatible when the best-fit surface-position definition is used. We propose alternative definitions of surface position that do not suffer from the same problems and consider their consequences for optical design and metrology.     

Mid-infrared materials and devices on a Si platform for optical sensing

In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiN_x waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors.     

Frequency-shifted optical feedback in a pumping laser diode dynamically amplified by a microchip laser

Compared with conventional optical heterodyne detection, laser optical feedback imaging (LOFI) allows for a several orders of magnitude higher intensity modulation contrast. The maximum contrast amplification is typically 10(3) for a diode laser in the gigahertz range and 10(6) for a microchip laser in the megahertz range. To take advantage of the wavelength tunability of a laser diode and of the lower resonant detection frequency of a microchip laser, we used LOFI modulation induced by the frequency-shifted optical feedback in a laser diode as a modulated pumping power for a microchip laser for resonant dynamic amplification. In this way, we were able to transfer the optical feedback sensitivity of the laser diode to the megahertz range. Application to telemetry is also reported.     

Concept of a miniature optical spectrometer using integrated optical and micro-optical components

We describe the concept of a super compact diffractive imaging spectrometer, with optical components a few millimeters across in all dimensions, capable of detecting optical fluorescence spectra within the entire visible spectral range from 400 nm to 700 nm with resolution of the order of 2 nm. In addition, the proposed spectrometer is capable of working simultaneously with multiple, up to 35, independent input optical channels. A specially designed diffractive optical element integrated with a planar optical waveguide is the key component of the proposed device. In the preliminary experimental tests, a uniform waveguide grating with a microlens was used to mimic operation of the diffractive optical element. A microspectrometer with optical components measured below 1 cm in all dimensions covers the spectral range from 450 nm to 650 nm and shows a spectral resolution of 0.5 nm at wavelengths close to 514 nm and 633 nm.     

全金属反射光学系统主镜的集成分析

光学集成分析是对外界力或热作用下系统光学性能的分析。全金属反射光学系统主镜的集成分析包括:在AutoCAD和Pro/E中进行结构设计,建立模型,于Ansys中进行有限元分析,在Zemax中进行光学分析。分析结果表明,横向20g加速度作用下主镜轴向变形最大,为0.869E-6m;轴向20g加速度作用下主镜的应力最大,为1.19MPa;在重力作用下,系统最大波前值分别为0.0387λ,在系统对光学性能0.05λ的要求范围内;在5~20g加速度范围内,主镜变形对系统RMS点尺寸的影响成近似的线性;近轴视场内,横向加速度对系统RMS点尺寸的影响比轴向的略小。光学集成分析可为光学系统的设计与评价提供更确切的依据。     

A general method for solving dynamically accelerating multiple co-linear cracks

We present a general method for analyzing dynamically accelerating multiple co-linear cracks that can be applied to the contexts of plane strain or antiplane shear in an elastic material. The difficulty in solving such problems lies in the fact that the space-time regions containing known data evolve as the crack propagates in an a priori unknown manner. Using an analog to a Dirichlet-to-Neumann map, we can find complete knowledge of the stress and displacement along the fracture plane, facilitating the application of fracture criteria that require these values away from the crack tip. The method is demonstrated for a semi-infinite or finite mode III crack as well as for a pair of cracks in elastic material, using a stress intensity factor fracture criterion for simplicity.     

Ray tracing formulas for monoaxial optical components

A formalism which allows finite ray tracing through monoaxial crystals was developed starting from Maxwell's equations. The derived formulas were applied to a Wollaston prism in convergent light and spot diagrams were obtained.